The complete characterization of a polymer microfluidic flow sensor is presented in this paper. The device fabrication is based on a combination of PCB and MEMS techniques, enabling effective thermal isolation and direct communication to the macroworld. The sensor performance can be tuned based on the precise definition of structural and operational parameters, these being the microchannel crossection, the sensing element positioning, and the sensor operating principle. By combining the aforementioned parameters, an extended measurement range and high sensitivity in specified flow rate regions can be achieved.